Obs. : 2008-08-04 Planet Ly alpha (photons/cm^2/sec) Mercury 3.432e+11 Venus 3.527e+11 Earth 3.450e+11 Mars 3.561e+11 Jupiter 3.510e+11 Saturn 3.527e+11 Uranus 3.386e+11 Neptune 3.450e+11 Pluto 3.560e+11